Anti-terrorism experts from around the world conclude a major conference in Belfast today that helped security forces from Australia to Sweden co-ordinate the fight against global terror.
The week-long conference is the second phase of a four-part course to allow counter-terrorism chiefs to share experiences.
Organised jointly by the PSNI, the FBI, Scotland's Police College and the Royal Canadian Mounted Police, this week the course became an intersection between the anniversary of 9/11 and the current battle against terrorism.
The 45 experts who took part in the Leadership in Counter-Terrorism Course spent the anniversary of the 2001 attacks looking at how policing evolved in Belfast.
They also attended a 9/11 service in the RUC GC memorial garden at Belfast's PSNI HQ.
They discussed the Whiterock riot of 2005 - which broke out when the course was last held in Belfast - with the PSNI commanders who dealt with it.
John Miller, the FBI's assistant director of public affairs, said the PSNI experience gave delegates the benefits of "intelligence and counter-terrorism based on years of development".
He said: "What we kind of scrambled together in the United States in the post 9/11 world was really embedded as a second front in policing here. There's an awful lot to learn from PSNI."
PSNI Det Supt Gary Gracey said one of the aims is to share information about recent events, wherever they happen.
He said: "We don't want historical events. We want real life in real time."
Real life collided with the course during its first phase in July, when failed car bombings in Hammersmith and at Glasgow airport happened as delegates were leaving Scotland.
One day Commander Ian Carter of the Metropolitan Police was sitting in the course with Special Agent Joseph Demarest of the FBI and Deputy Chief James Waters of the NYPD. The next they were all in a high level London briefing.
"What you had in the first session of this course was a situation where they had come to talk about the broad operational and even academic elements of the subject, and reality and theory clashed immediately, before we were even done talking about it," said Mr Miller.
Mr Carter said that briefing was an example of how the Counter Terrorism Course "effectively breaks down barriers". Instead of the Met briefing strangers, he was dealing with officers he already knew.
"Relationships and partnerships in this business are critical. It helps break down the barriers," said Special Agent Demarest, a member of the same task force. "The core issues are much more similar than different. And we find we're all similar in personality, approach, passion, commitment. The nice thing is because everybody's in the business and the door is closed, nobody has to watch what they say," said Mr Miller. "They tell you what they always tell you, which is everything they did right.
"But the best tools you leave here with are the second half of that, where they tell you everything they did wrong and what they learned from that. That's been extraordinarily beneficial because everybody knows that maybe next week I'm going to be sitting in that hot seat and I can put all this to work right now."
This is the third time the course - run over four separate weeks throughout one year - has been put together. About 135 law enforcement people have taken part, 14 from the PSNI.
On the anniversary of 9/11 the 45 delegates for this course gathered in the RUC GC memorial garden for a service conducted by the Bishop of New York, Mark Sisk, and the Dean of Belfast Cathedral, Houston McKelvey.
"You've got this beautiful setting, you've got the names of over 300 police officers inscribed in the garden who are victims of terrorism of a different kind over another period, and you've got a bishop from New York talking about the services he did after September 11 and the dean from Belfast talking about the police officers he buried," said Mr Miller. " It was extraordinarily moving.
He added: "We're all fighting the same type of bad guys, we're all paying the same terrible price, and we're all half a world away reflecting on that."
Said Ian Carter: "The bottom line is that actually we're able to make the world a better place."